[linux-2.6-block.git] / drivers / mtd / devices / mchp23k256.c

/*
 * mchp23k256.c
 *
 * Driver for Microchip 23k256 SPI RAM chips
 *
 * Copyright © 2016 Andrew Lunn <andrew@lunn.ch>
 *
 * This code is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 */
#include <linux/device.h>
#include <linux/module.h>
#include <linux/mtd/mtd.h>
#include <linux/mtd/partitions.h>
#include <linux/mutex.h>
#include <linux/sched.h>
#include <linux/sizes.h>
#include <linux/spi/flash.h>
#include <linux/spi/spi.h>
#include <linux/of_device.h>

#define MAX_CMD_SIZE		4

struct mchp23_caps {
	u8 addr_width;
	unsigned int size;
};

struct mchp23k256_flash {
	struct spi_device	*spi;
	struct mutex		lock;
	struct mtd_info		mtd;
	const struct mchp23_caps	*caps;
};

#define MCHP23K256_CMD_WRITE_STATUS	0x01
#define MCHP23K256_CMD_WRITE		0x02
#define MCHP23K256_CMD_READ		0x03
#define MCHP23K256_MODE_SEQ		BIT(6)

#define to_mchp23k256_flash(x) container_of(x, struct mchp23k256_flash, mtd)

static void mchp23k256_addr2cmd(struct mchp23k256_flash *flash,
				unsigned int addr, u8 *cmd)
{
	int i;

	/*
	 * Address is sent in big endian (MSB first) and we skip
	 * the first entry of the cmd array which contains the cmd
	 * opcode.
	 */
	for (i = flash->caps->addr_width; i > 0; i--, addr >>= 8)
		cmd[i] = addr;
}

static int mchp23k256_cmdsz(struct mchp23k256_flash *flash)
{
	return 1 + flash->caps->addr_width;
}

static int mchp23k256_write(struct mtd_info *mtd, loff_t to, size_t len,
			    size_t *retlen, const unsigned char *buf)
{
	struct mchp23k256_flash *flash = to_mchp23k256_flash(mtd);
	struct spi_transfer transfer[2] = {};
	struct spi_message message;
	unsigned char command[MAX_CMD_SIZE];
	int ret;

	spi_message_init(&message);

	command[0] = MCHP23K256_CMD_WRITE;
	mchp23k256_addr2cmd(flash, to, command);

	transfer[0].tx_buf = command;
	transfer[0].len = mchp23k256_cmdsz(flash);
	spi_message_add_tail(&transfer[0], &message);

	transfer[1].tx_buf = buf;
	transfer[1].len = len;
	spi_message_add_tail(&transfer[1], &message);

	mutex_lock(&flash->lock);

	ret = spi_sync(flash->spi, &message);

	mutex_unlock(&flash->lock);

	if (ret)
		return ret;

	if (retlen && message.actual_length > sizeof(command))
		*retlen += message.actual_length - sizeof(command);

	return 0;
}

static int mchp23k256_read(struct mtd_info *mtd, loff_t from, size_t len,
			   size_t *retlen, unsigned char *buf)
{
	struct mchp23k256_flash *flash = to_mchp23k256_flash(mtd);
	struct spi_transfer transfer[2] = {};
	struct spi_message message;
	unsigned char command[MAX_CMD_SIZE];
	int ret;

	spi_message_init(&message);

	memset(&transfer, 0, sizeof(transfer));
	command[0] = MCHP23K256_CMD_READ;
	mchp23k256_addr2cmd(flash, from, command);

	transfer[0].tx_buf = command;
	transfer[0].len = mchp23k256_cmdsz(flash);
	spi_message_add_tail(&transfer[0], &message);

	transfer[1].rx_buf = buf;
	transfer[1].len = len;
	spi_message_add_tail(&transfer[1], &message);

	mutex_lock(&flash->lock);

	ret = spi_sync(flash->spi, &message);

	mutex_unlock(&flash->lock);

	if (ret)
		return ret;

	if (retlen && message.actual_length > sizeof(command))
		*retlen += message.actual_length - sizeof(command);

	return 0;
}

/*
 * Set the device into sequential mode. This allows read/writes to the
 * entire SRAM in a single operation
 */
static int mchp23k256_set_mode(struct spi_device *spi)
{
	struct spi_transfer transfer = {};
	struct spi_message message;
	unsigned char command[2];

	spi_message_init(&message);

	command[0] = MCHP23K256_CMD_WRITE_STATUS;
	command[1] = MCHP23K256_MODE_SEQ;

	transfer.tx_buf = command;
	transfer.len = sizeof(command);
	spi_message_add_tail(&transfer, &message);

	return spi_sync(spi, &message);
}

static const struct mchp23_caps mchp23k256_caps = {
	.size = SZ_32K,
	.addr_width = 2,
};

static const struct mchp23_caps mchp23lcv1024_caps = {
	.size = SZ_128K,
	.addr_width = 3,
};

static int mchp23k256_probe(struct spi_device *spi)
{
	struct mchp23k256_flash *flash;
	struct flash_platform_data *data;
	int err;

	flash = devm_kzalloc(&spi->dev, sizeof(*flash), GFP_KERNEL);
	if (!flash)
		return -ENOMEM;

	flash->spi = spi;
	mutex_init(&flash->lock);
	spi_set_drvdata(spi, flash);

	err = mchp23k256_set_mode(spi);
	if (err)
		return err;

	data = dev_get_platdata(&spi->dev);

	flash->caps = of_device_get_match_data(&spi->dev);
	if (!flash->caps)
		flash->caps = &mchp23k256_caps;

	mtd_set_of_node(&flash->mtd, spi->dev.of_node);
	flash->mtd.dev.parent	= &spi->dev;
	flash->mtd.type		= MTD_RAM;
	flash->mtd.flags	= MTD_CAP_RAM;
	flash->mtd.writesize	= 1;
	flash->mtd.size		= flash->caps->size;
	flash->mtd._read	= mchp23k256_read;
	flash->mtd._write	= mchp23k256_write;

	err = mtd_device_register(&flash->mtd, data ? data->parts : NULL,
				  data ? data->nr_parts : 0);
	if (err)
		return err;

	return 0;
}

static int mchp23k256_remove(struct spi_device *spi)
{
	struct mchp23k256_flash *flash = spi_get_drvdata(spi);

	return mtd_device_unregister(&flash->mtd);
}

static const struct of_device_id mchp23k256_of_table[] = {
	{
		.compatible = "microchip,mchp23k256",
		.data = &mchp23k256_caps,
	},
	{
		.compatible = "microchip,mchp23lcv1024",
		.data = &mchp23lcv1024_caps,
	},
	{}
};
MODULE_DEVICE_TABLE(of, mchp23k256_of_table);

static struct spi_driver mchp23k256_driver = {
	.driver = {
		.name	= "mchp23k256",
		.of_match_table = of_match_ptr(mchp23k256_of_table),
	},
	.probe		= mchp23k256_probe,
	.remove		= mchp23k256_remove,
};

module_spi_driver(mchp23k256_driver);

MODULE_DESCRIPTION("MTD SPI driver for MCHP23K256 RAM chips");
MODULE_AUTHOR("Andrew Lunn <andre@lunn.ch>");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("spi:mchp23k256");
Commit	Line	Data
5dc17fa6 AL	1	/*
	2	* mchp23k256.c
	3	*
	4	* Driver for Microchip 23k256 SPI RAM chips
	5	*
	6	* Copyright © 2016 Andrew Lunn <andrew@lunn.ch>
	7	*
	8	* This code is free software; you can redistribute it and/or modify
	9	* it under the terms of the GNU General Public License version 2 as
	10	* published by the Free Software Foundation.
	11	*
	12	*/
	13	#include <linux/device.h>
	14	#include <linux/module.h>
	15	#include <linux/mtd/mtd.h>
	16	#include <linux/mtd/partitions.h>
	17	#include <linux/mutex.h>
	18	#include <linux/sched.h>
	19	#include <linux/sizes.h>
	20	#include <linux/spi/flash.h>
	21	#include <linux/spi/spi.h>
4db4d35e	22	#include <linux/of_device.h>
5dc17fa6	23
4379075a CP	24	#define MAX_CMD_SIZE 4
	25
	26	struct mchp23_caps {
	27	u8 addr_width;
	28	unsigned int size;
	29	};
	30
5dc17fa6 AL	31	struct mchp23k256_flash {
	32	struct spi_device *spi;
	33	struct mutex lock;
	34	struct mtd_info mtd;
4379075a	35	const struct mchp23_caps *caps;
5dc17fa6 AL	36	};
	37
	38	#define MCHP23K256_CMD_WRITE_STATUS 0x01
	39	#define MCHP23K256_CMD_WRITE 0x02
	40	#define MCHP23K256_CMD_READ 0x03
	41	#define MCHP23K256_MODE_SEQ BIT(6)
	42
	43	#define to_mchp23k256_flash(x) container_of(x, struct mchp23k256_flash, mtd)
	44
4379075a CP	45	static void mchp23k256_addr2cmd(struct mchp23k256_flash *flash,
	46	unsigned int addr, u8 *cmd)
	47	{
	48	int i;
	49
	50	/*
	51	* Address is sent in big endian (MSB first) and we skip
	52	* the first entry of the cmd array which contains the cmd
	53	* opcode.
	54	*/
	55	for (i = flash->caps->addr_width; i > 0; i--, addr >>= 8)
	56	cmd[i] = addr;
	57	}
	58
	59	static int mchp23k256_cmdsz(struct mchp23k256_flash *flash)
	60	{
	61	return 1 + flash->caps->addr_width;
	62	}
	63
5dc17fa6 AL	64	static int mchp23k256_write(struct mtd_info *mtd, loff_t to, size_t len,
	65	size_t retlen, const unsigned char buf)
	66	{
	67	struct mchp23k256_flash *flash = to_mchp23k256_flash(mtd);
	68	struct spi_transfer transfer[2] = {};
	69	struct spi_message message;
4379075a	70	unsigned char command[MAX_CMD_SIZE];
db601f3a	71	int ret;
5dc17fa6 AL	72
	73	spi_message_init(&message);
	74
	75	command[0] = MCHP23K256_CMD_WRITE;
4379075a	76	mchp23k256_addr2cmd(flash, to, command);
5dc17fa6 AL	77
5dc17fa6 AL	78	transfer[0].tx_buf = command;
4379075a	79	transfer[0].len = mchp23k256_cmdsz(flash);
5dc17fa6 AL	80	spi_message_add_tail(&transfer[0], &message);
	81
	82	transfer[1].tx_buf = buf;
	83	transfer[1].len = len;
	84	spi_message_add_tail(&transfer[1], &message);
	85
	86	mutex_lock(&flash->lock);
	87
db601f3a AB	88	ret = spi_sync(flash->spi, &message);
	89
	90	mutex_unlock(&flash->lock);
	91
	92	if (ret)
	93	return ret;
5dc17fa6 AL	94
	95	if (retlen && message.actual_length > sizeof(command))
	96	*retlen += message.actual_length - sizeof(command);
	97
5dc17fa6 AL	98	return 0;
	99	}
	100
	101	static int mchp23k256_read(struct mtd_info *mtd, loff_t from, size_t len,
	102	size_t retlen, unsigned char buf)
	103	{
	104	struct mchp23k256_flash *flash = to_mchp23k256_flash(mtd);
	105	struct spi_transfer transfer[2] = {};
	106	struct spi_message message;
4379075a	107	unsigned char command[MAX_CMD_SIZE];
db601f3a	108	int ret;
5dc17fa6 AL	109
	110	spi_message_init(&message);
	111
	112	memset(&transfer, 0, sizeof(transfer));
	113	command[0] = MCHP23K256_CMD_READ;
4379075a	114	mchp23k256_addr2cmd(flash, from, command);
5dc17fa6 AL	115
5dc17fa6 AL	116	transfer[0].tx_buf = command;
4379075a	117	transfer[0].len = mchp23k256_cmdsz(flash);
5dc17fa6 AL	118	spi_message_add_tail(&transfer[0], &message);
	119
	120	transfer[1].rx_buf = buf;
	121	transfer[1].len = len;
	122	spi_message_add_tail(&transfer[1], &message);
	123
	124	mutex_lock(&flash->lock);
	125
db601f3a AB	126	ret = spi_sync(flash->spi, &message);
	127
	128	mutex_unlock(&flash->lock);
	129
	130	if (ret)
	131	return ret;
5dc17fa6 AL	132
	133	if (retlen && message.actual_length > sizeof(command))
	134	*retlen += message.actual_length - sizeof(command);
	135
5dc17fa6 AL	136	return 0;
	137	}
	138
	139	/*
	140	* Set the device into sequential mode. This allows read/writes to the
	141	* entire SRAM in a single operation
	142	*/
	143	static int mchp23k256_set_mode(struct spi_device *spi)
	144	{
	145	struct spi_transfer transfer = {};
	146	struct spi_message message;
	147	unsigned char command[2];
	148
	149	spi_message_init(&message);
	150
	151	command[0] = MCHP23K256_CMD_WRITE_STATUS;
	152	command[1] = MCHP23K256_MODE_SEQ;
	153
	154	transfer.tx_buf = command;
	155	transfer.len = sizeof(command);
	156	spi_message_add_tail(&transfer, &message);
	157
	158	return spi_sync(spi, &message);
	159	}
	160
4379075a CP	161	static const struct mchp23_caps mchp23k256_caps = {
	162	.size = SZ_32K,
	163	.addr_width = 2,
	164	};
	165
	166	static const struct mchp23_caps mchp23lcv1024_caps = {
	167	.size = SZ_128K,
	168	.addr_width = 3,
	169	};
	170
5dc17fa6 AL	171	static int mchp23k256_probe(struct spi_device *spi)
	172	{
	173	struct mchp23k256_flash *flash;
	174	struct flash_platform_data *data;
	175	int err;
	176
	177	flash = devm_kzalloc(&spi->dev, sizeof(*flash), GFP_KERNEL);
	178	if (!flash)
	179	return -ENOMEM;
	180
	181	flash->spi = spi;
	182	mutex_init(&flash->lock);
	183	spi_set_drvdata(spi, flash);
	184
	185	err = mchp23k256_set_mode(spi);
	186	if (err)
	187	return err;
	188
	189	data = dev_get_platdata(&spi->dev);
	190
4379075a CP	191	flash->caps = of_device_get_match_data(&spi->dev);
	192	if (!flash->caps)
	193	flash->caps = &mchp23k256_caps;
	194
2f071ff1	195	mtd_set_of_node(&flash->mtd, spi->dev.of_node);
5dc17fa6 AL	196	flash->mtd.dev.parent = &spi->dev;
	197	flash->mtd.type = MTD_RAM;
	198	flash->mtd.flags = MTD_CAP_RAM;
	199	flash->mtd.writesize = 1;
4379075a	200	flash->mtd.size = flash->caps->size;
5dc17fa6 AL	201	flash->mtd._read = mchp23k256_read;
	202	flash->mtd._write = mchp23k256_write;
	203
44225c9c CP	204	err = mtd_device_register(&flash->mtd, data ? data->parts : NULL,
44225c9c CP	205	data ? data->nr_parts : 0);
5dc17fa6 AL	206	if (err)
	207	return err;
	208
	209	return 0;
	210	}
	211
	212	static int mchp23k256_remove(struct spi_device *spi)
	213	{
	214	struct mchp23k256_flash *flash = spi_get_drvdata(spi);
	215
	216	return mtd_device_unregister(&flash->mtd);
	217	}
	218
4db4d35e	219	static const struct of_device_id mchp23k256_of_table[] = {
4379075a CP	220	{
	221	.compatible = "microchip,mchp23k256",
	222	.data = &mchp23k256_caps,
	223	},
	224	{
	225	.compatible = "microchip,mchp23lcv1024",
	226	.data = &mchp23lcv1024_caps,
	227	},
4db4d35e CP	228	{}
	229	};
	230	MODULE_DEVICE_TABLE(of, mchp23k256_of_table);
	231
5dc17fa6 AL	232	static struct spi_driver mchp23k256_driver = {
	233	.driver = {
	234	.name = "mchp23k256",
4db4d35e	235	.of_match_table = of_match_ptr(mchp23k256_of_table),
5dc17fa6 AL	236	},
	237	.probe = mchp23k256_probe,
	238	.remove = mchp23k256_remove,
	239	};
	240
	241	module_spi_driver(mchp23k256_driver);
	242
	243	MODULE_DESCRIPTION("MTD SPI driver for MCHP23K256 RAM chips");
	244	MODULE_AUTHOR("Andrew Lunn <andre@lunn.ch>");
	245	MODULE_LICENSE("GPL v2");
	246	MODULE_ALIAS("spi:mchp23k256");